Ellipsograph



a Patented Nov. 13, 17951n U1\Il'['l:`.l) STATES PATENT F'FIC (Granted under the act of March 3, 1883,V as amended April 30, 1928; 370 C). G. 757) 6 Claims.

This invention relates to ellipsographs and more particularly to ellipsographs which will draw ellipses of large size and large eccentricity.

Most ellipsographs are very limited in their scope and will not draw ellipses of large eccentricity or large size.

It is an object of this invention to provide an ellipsograph of simple construction.

It is another object of this invention to provide an ellipsograph which will draw an ellipse of any desired eccentricity and any size 'within its upper limits.

It is another object of this invention to provie'd an ellipsograph which is very simple in operation and does not require skilled personnel to operate.

A still further object of this invention is to provide an ellipsograph which, during the scribing of the ellipse, can be removed and then replaced in position to finish the ellipse, without displacement.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description.

The apparatus of this invention comprises generally a pair of spaced pivots on a base bar, to which are pivotally mounted a pair of actuating arms, capable of rotation in acommon plane. A rst cross member spans the pair of actuating arms and is pivotally connected thereto by means of adjustable slides. A second cross member similarly spans the actuating arms and is pivotally and slidably connected thereto in the same manner as the first cross member. The second cross member has a transverse member 'fixed perpendicular theretoand intersecting the rst cross member. The transverse member and the rst cross member are connected together at their intersection by means of a scriber member free to slide on eithercf the above members, the scriber member having a suitable pen or pencil holder attached to draw the ellipse.

In use the sliders common to the rst cross member and the actuating arms are set at a distance from the pivots equal to the half minor axis of the required ellipse. The sliders common to the second cross member and the actuating arms are set at a distance equal to the half major axis of the ellipse. Then by swinging the actuating arms, the scriber member at the intersection of the transverse member and the rst cross member will describe an ellipse.

The second cross member is offset outwardly at the point where the transverse arm ismounted to permit the pivots of the two cross members to be set coaxially.

In the modifications described, only one half of an ellipse will be drawn at one time. However, the apparatus is provided with a pair of removable .pins extending outwardly from the bottom of the bar and in line with the pivots. The pins vcan bepressed into the surface of a drafting table and the ellipsograph can then be lifted, turned 180.", and replaced on the pins to complete the second half oi the ellipse which will register with the rst half.

To facilitate the correct spacing of the pins without having to use the complete instrument, a spacing bar having a pair of holes therein to receive the pins may be used.

Two embodiments of the instant invention have been illustrated in the accompanying drawings, wherein:

Fig. 1 is a top plan view of an embodiment of the ellipsograph;

Fig. 2 is a side view of the Fig. 1 embodiment;

Fig. 3 is a top plan view of a second embodiment of the instant invention;

Fig. 4 is af partial section taken on line 4 4 of Fig. 3;

Fig. 5 is .a plan view partially broken away, of Fig. 4;

Fig. 6 is a plan view of the spacing bar;

Fig. 7 is a side view of the spacing bar; and

Fig. 8 is a detail View of the removable pin.

Referring to Figs. 1 and 2 of the drawing, II designates a base bar having at its ends transverse extensions I5 terminating in a pair of spaced pivots I2, to which are mounted a pair of actuating arms I3, capable of rotation in a common plane. Slides I4 are slidably mounted, two to each of the arms I3, and can be locked in selective positions on the arms I3 by means of the set screws I6. A cross member I'I spans the actuatingV arms I3 and is pivotally connected at I8 to a pair of the sliders I4. A second cross member I9 similarly spans the arms I3, and is pivotally connected at 2I to the second pair of sliders I 4. The second cross member I9 has a transverse member 22 mounted thereon perpendicular thereto and intersecting the cross member I1. v

The transverse member 22 and the cross member II are connected together by means of a sliding scriber member 23 free to slide on either the cross member Il or the transverse member 22. The scriber member 23 is provided with a suitable holder 2s, for a pen or pencil attached to draw the ellipse.

The cross member I9 is offset outwardly at 2S to provide clearance for the scriber member 23 when the pivoted actuating arms are at the limits of their swing and when ellipses of small eccentricities are to be drawn.

Operation In operation, the pvot points 2| of the cross member I9 are serl at a distance from the pivots I2 equal to half the major axis of the desired ellipse by sliding the sliders I4 inwardly or outwardly (toward or away from pivots I2) along the actuating arms I3. The sliders are then locked into position by means of the set screws I5. The pivot points I8 of the cross arm I1 are set in a like manner, at a distance from the pivots I2 equal to half the minor axis of the desired ellipse and are likewise locked into position. The maximum major axis which may be used is equal to the distance between the supports of the pivots I2 of the actuating arms or twice the length of the usable length of the actuating arms. Rotating or oscillating the actuating arms I3, 180 about the pivots I2, the pen or pencil in holder 24 on the sliding scriber member 23 will describe a longitudinal half of an ellipse. It is obvious that with this embodiment of the instant invention it is necessary to draw an ellipse in two separate halves.

Second embodiment To facilitate the completion of an entire ellipse Without any displacement of the lines, the Fig. 3 embodiment is provided. This embodiment is generally similar to that of Fig. l. However, the bar I I has been replaced by a pair of pivot plates Ila, having a, base portion 21, a leg portion 28, and a top portion 29. The actuating arms I3a arepivoted to the top portion 29 by means of the pivots I2a. counterbored hole 3l, in line with the pivot I2a, adapted to receive a removable pin 32 having a point 33 extending downwardly from the base portion 21.

In operation, the instant embodiment is placed intoposition one. drafting table and secured from lateral movement by pressing the points 33 of the pins 32 into the surface of the table. The procedure described for the operation of the rst embodiment is then followed and the first half of the ellipse is drawn. The apparatus is then lifted bodily from the table, leaving the pins 32 in place on the table. The apparatus is then turned 180 into position to draw the second half of the ellipse, replaced on the pins 32, and the second half of the ellipse is completed. Since the pins 32 and the pivots I2a are on the longitudinal axis of the ellipse, and since this position has been maintained for both halves of the ellipse, there will be no displacement between the two halves and they will register perfectly.

To further simplify the operation of the above embodiment and to obviate the necessity for using the free swinging ellipsograph for positioning the removable pins 32 on the drawing table, a guide bar 34 (Fig. 6 and 7) is provided, having a pair of spaced holes 36 to receive the pins 32. The holes 36 are spaced equal to the spacing between the pairs of pivot points I8 and 2I on the cross members I1 and I9 respectively. The guide bar 34, carrying the pins 32 in the holes 36 therein, is placed over the longitudinal axis of the desired ellipse and the pins pushed into the drawing `table. The bar 34 is then removed. The ellipsograph, when subsequentlyplaced over `the The base portion 21 has therein a pins 32, is then in position to draw the ellipse.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or for the Government of .the United States of America, for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

l. An ellipsograph comprising a pair of spaced pivots, said pivots having a pair of spaced removable pins extending from the bottom surface thereof whereby by pressing said pins into the surfaceof a draftingtable said ellipsograph may be removed and subsequently replaced in its previous or reversed position without misalignment, aV pair of actuating arms pivotably mounted on said pivots for rotation in a common plane, a pair of sliders slidably mounted on each of said actuating arms and having locking means for selectively locking said sliders to said actuating arms at selective distances from the point of pivot, a rst cross'member spanning said arms and pivoted at each end to one of said pair 0f. sliders on each of said arms, asecond cross member spanning said arms and pivoted to the other one of said pair of sliders on each of said arms, and having a transverse member intersecting said first cross member, said second cross member being offset outwardly at its juncture with said transverse member, and a scriber member mounted slidably on said transverse member and said first crossmember at their intersection.

2. An ellipsograph comprising a pair of spaced pivots, said pivots having a vpair of spaced removable pins extending from the bottom surface thereof whereby by pressing said pins into the surfaceof a drafting table said ellipsograph may be removed and subsequently replaced in its previous or reversed position without misalignment, a pair of actuating arms pivotably mounted on said pivotsforrotation in a common plane, a pair of sliders slidably `mounted on each of said actuating arms having locking means for selectively locking said sliders to said actuating arms at selective distances from the point of pivot, a first cross member spanning said arms and pivoted at each end to one of said pair of sliders on each of said arms, a second cross member spanning said arms and pivoted to the other one of said pair of sliders on each of said arms, and having a transverse member intersecting said first cross member, and a scriber member mounted slidably on said transverse member and said first cross Vmember' at their intersection.

3. An ellipsograph comprising a-pair of spaced pivots, a pair of actuating arms pivotably mounted on said pivots for rotationin a common plane, a .pair vof sliders slidably mounted on each of said actuating .arms having locking means for selectively locking said sliders to said actuating arms at selective distances from the point of pivot, a Yfirst cross member spanning said arms and pivoted at each end to one of said pair of sliders on each of said arms, a second cross member spanning said arms and pivoted to the therone of said pair of sliders on each 0f said arms; and having a transverse member rintersecting,r said rst cross member, and a scriber member mounted :slidably `on said transverse tersection.

4. An ellipsograph comprising a pair of spaced pivots, a pair of actuating arms pivotably mounted on said pivots for rotation in a common plane, a first cross member spanning said actuating arms and pivoted thereto, a second cross member spanning said actuating arms and pivoted thereto, and having a transverse member intersecting said first cross member, and a scriber member mounted slidably on said transverse member and said rst cross member at their intersection.

5. An ellipsograph comprising a pair of spaced actuating arms pivotably mounted for rotation in a common plane, a first cross member spanning said actuating arms and pivoted thereto, a second cross member spanning said actuating arms and pivoted thereto, and having a transverse member intersecting said first cross member, and a scriber member mounted slidably on said transverse member and said rst cross member at their intersection.

6. An ellipsograph comprising a pair of pivot members xedly spaced from each other, a pair of removable pins extending from the bottom surfaces of the pivot members whereby by pressing said pins into the surface of a drafting table said ellipsograph may be -removed and subsequently replaced in its previous or reversed position without misalignment, a pair of parallel actuating arms pivotally mounted on said pivot members for rotation in a common plane, a pair of sliders slidably mounted on each of said actuating arms, means for selectively locking said sliders to said actuating arms at selective distances from the point of pivot, a rst cross member spanning said arms and pivoted at each end to one of said pair of sliders on each of said arms, a second cross member spanning said arms and pivoted to the other one of said pair of sliders on eachy of said arms, a transverse member fixed to said second cross member extending inwardly therefrom and intersecting said rst cross member, said second cross member being offset outwardly at its juncture with said transverse member, and a scriber member mounted slidably on said transverse member and said first cross member at their intersection.

WILLIAM H. CHRISTIE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 918,218 Sundman Apr. 13, 1909 FOREIGN PATENTS Number Country Date 114,711 Switzerland Apr. 16, 1926 

